1. Model-Centric Engineering, Part 1: An Introduction to Model-Based Systems Engineering Presenter: Daniel L Dvorak Copyright 2013 California Institute of Technology. U.S. Government sponsorship acknowledged.

2. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Audience, Prerequisites Intended Audience: Systems engineers and managers seeking to understand MBSE*: definition, motivations, claimed benefits, etc. Prerequisites: Systems engineering background Non-Objectives:  Not SysML** training  Not tool training * MBSE = Model-Based Systems Engineering ** SysML = Systems Modeling Language * MBSE = Model-Based Systems Engineering ** SysML = Systems Modeling Language 2

3. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Model-Centric Engineering Series Module 1 (~1¼ hours) Systems Engineering with System Models Module 1 (~1¼ hours) Systems Engineering with System Models Module 2 (~1½ hours) Introduction to System Modeling Module 2 (~1½ hours) Introduction to System Modeling Module 3 (~3 hours) Foundational Concepts for Building System Models Module 3 (~3 hours) Foundational Concepts for Building System Models Primary Audience Managers and systems engineers Systems engineers & discipline engineers Model developers (a subset of systems & discipline engineers) Module 4 (~2½ hours) Architecting the System Model Module 4 (~2½ hours) Architecting the System Model Project leadership (ensure that the model provides value to project) 3

4. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Acknowledgments Contributors: Todd Bayer, Daniel Dvorak, Sanford Friedenthal*, J. Steve Jenkins, Chi Lin, Sanda Mandutianu Other sources: Europa Study systems engineering team JPL Modeling Early Adopters community Funding: NASA Chief Engineer (Mike Ryschkewitsch) –SEWG MBSE initiative (Joseph Smith, HQ) JPL ESD Integrated Model-Centric Engineering (Chi Lin, JPL) JPL Systems & Software Division (David Nichols, JPL) 4 * Affiliation: SAF Consulting

5. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Outline ① What is model-based systems engineering (MBSE)? ② Systems engineering problems that MBSE addresses ③ The role of a system model and how it relates to other discipline models ④ Case study in MBSE ⑤ Comparison of MBSE to traditional SE ⑥ Management issues: –Implications for projects, infusion strategy, lessons learned ⑦ Summary 5

6. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Preview of Key Points  MBSE is SE. It formalizes part of SE; it doesn’t replace it.  MBSE helps enhance communication, manage complexity, and improve product quality  The “system model” plays an integrating role with respect to the various discipline models in a project  Effective models organize rich technical information, disclose inconsistencies, support analyses and verification, support automated generation of gate products, and preserve technical investments  Infusion of MBSE involves some learning curve and culture change, so plan for it 6

7. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What is Model-Based Systems Engineering, and what’s the Big Idea? 7

8. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What is MBSE / MBE? “Model-Based Engineering (MBE): An approach to engineering that uses models as an integral part of the technical baseline that includes the requirements, analysis, design, implementation, and verification of a capability, system, and/or product throughout the acquisition life cycle.” Final Report, Model-Based Engineering Subcommittee, NDIA, Feb. 2011 “Model-Based Engineering (MBE): An approach to engineering that uses models as an integral part of the technical baseline that includes the requirements, analysis, design, implementation, and verification of a capability, system, and/or product throughout the acquisition life cycle.” Final Report, Model-Based Engineering Subcommittee, NDIA, Feb. 2011 “Model-based systems engineering (MBSE) is the formalized application of modeling to support system requirements, design, analysis, verification and validation activities beginning in the conceptual design phase and continuing throughout development and later life cycle phases.” INCOSE SE Vision 2020 (INCOSE-TP-2004-004-02, Sep 2007) “Model-based systems engineering (MBSE) is the formalized application of modeling to support system requirements, design, analysis, verification and validation activities beginning in the conceptual design phase and continuing throughout development and later life cycle phases.” INCOSE SE Vision 2020 (INCOSE-TP-2004-004-02, Sep 2007) 8

9. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Comparing Document-Based SE to MBSE  Document-based SE produces a variety of documents  Difficult to …  assess completeness and consistency of information spread across several documents  perform traceability  assess change impacts  MBSE produces a system model, held in a model repository  Includes system specification, design, analysis and verification  Provides a more complete, consistent and traceable system design  Facilitates traceability and change impact assessments 9 Source: Sanford Friedenthal

10. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What’s the Big Idea of MBSE? Add rigor and precision (enhance communication) Help manage complexity 10 Electronic and mechanical CAD went through similar transformations over the last 30 years

11. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE in two dimensions MBSE (and SE) … Spans the engineering life-cycle Integrates with multiple engineering disciplines Vertical Integration System Model Subsystem Models Component Models Pre-Phase A Concept Studies Phase A Concept & Technology Dev Phase B Preliminary Design Phase C Final Design & Fabrication Phase D Assembly, Test & Launch Phase E Operations & Sustainment 11

12. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE The “System Model” Today: Standalone models related through documents Future: Shared system model with multiple views, and connected to discipline models  Systems Engineering requires structural, behavioral, physics and simulation- based models representing the technical designs  Current practice tends to rely on standalone (discipline-specific) models  MBSE moves toward a shared system model. All disciplines, including discipline-specific models, “view” a consistent system model. 12

13. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Myths about MBSE (part 1) Myth 1: MBSE is a new craze meant to displace traditional systems engineering No. MBSE formalizes part of SE to improve precision and rigor. It doesn't displace or replace it. Myth 2: MBSE is an additional SE activity No. MBSE is systems engineering, just as ECAD is electrical engineering. Myth 3: MBSE aims to eliminate documents No. Documents are still important. What's different in MBSE is that some documents can be generated from an authoritative, integrated system model, and therefore be kept mutually consistent and up to date. 13

14. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What problems exist in systems engineering? Source: “The Need for an Integrated Model-Centric Engineering Environment at JPL”, 24 Oct 2009, Todd Bayer (JPL IOM-3100-09-040)

15. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Problems in Systems Engineering (1 of 5) 15 Complexity Scope ?! Mission complexity is growing faster than our ability to manage it Result: Increasing mission risk from inadequate specification & incomplete verification

16. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Problems in Systems Engineering (2 of 5) 16 System design emerges from the pieces, not from an architecture Result: Systems that are brittle, difficult to test, and complex and expensive to operate

17. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Problems in Systems Engineering (3 of 5) 17 Knowledge and investment are lost at project lifecycle phase boundaries Result: Increasing development cost and risk of late discovery of design problems Phase n Phase n+1

18. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Problems in Systems Engineering (4 of 5) 18 Knowledge and investment are lost between projects Result: Increasing cost and risk; dampens potential for true product lines Project A Project B

19. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Problems in Systems Engineering (5 of 5) 19 Technical and programmatic sides of projects are poorly coupled Result: Hampers effective project decision-making, increasing development risk ?

20. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Industry-Identified Problems in SE* Poor integration of models across the life cycle –Hard to get coherent, checkable model of the whole system (at some level of abstraction) Limited reuse of models between programs –Paying for similar engineering work over and over Variation in modeling maturity and integration across Engineering Disciplines (e.g., systems, software, mechanical, electrical, test, maintainability, safety, security) –Mechanical/Electrical CAD/CAE fairly mature –Systems/Software/Test fairly immature * Source: NDIA Final Report, Model Based Engineering Subcommittee 20

21. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Current State “System Model” Spreadsheets, viewgraphs, text documents, e-mails, meeting notes, etc. “System Model” Spreadsheets, viewgraphs, text documents, e-mails, meeting notes, etc. Structural Model Power Model Thermal Model Radiation Model Margin Analysis Requirements & Objectives Configuration Operations Plan Desired State –Architecture and design captured in a formalized and repeatable system model –Design reviews consist largely of model inspection & validation –System model evolves from formulation through operations –System test activities focus on model validation –Models and modeling tools are integrated across life-cycle –Behavioral, physical, cost and risk models are integrated, allowing for an integrated fully- informed approach to system optimization Cost Model System Model Coupled models of structure, behavior, requirements, and equations. Single source of info. Checkable. Queryable. System Model Coupled models of structure, behavior, requirements, and equations. Single source of info. Checkable. Queryable. 21

22. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE How does MBSE address these problems? Getting to the desired state builds upon … –The concept of a formal system model, and –A standard modeling language 22

23. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What is a system model? What role does it play?

24. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What is a System Model? Structure Requirements Parametrics (equations) Behavior 24 A system model is an interconnected set of model elements that represent key system aspects including: structure, behavior, requirements, and parametrics A system model represents logical relationships among requirements, design, analysis and verification elements A system model is an interconnected set of model elements that represent key system aspects including: structure, behavior, requirements, and parametrics A system model represents logical relationships among requirements, design, analysis and verification elements

25. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE System Model as Integrator © Copyright Lockheed Martin Corporation All Rights Reserved System Model Req’ts Allocation & Design Integration Software Models Hardware Models Q Q SET CLR S R  G(s)U(s) Analysis Models Verification Models The system model exchanges information with discipline models to form an authoritative, up-to-date source of information at a system level 25

26. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE How a System Model Helps A system model can be structured to answer specific questions Does every component trace to a requirement? Have both sides of every interface been specified? If this requirement changes, what is potentially affected? What is the dry mass of the flight system? Show power and energy used for mission scenario x What is the mass rollup? Yes No! 479 kg System Model System Model List of functions, components, interfaces and requirements Power and energy profile MEL Using traditional methods: Manual mapping from every powerpoint block diagram to DOORS. Manual mapping from every powerpoint block diagram to every ICD. DOORS trace gives only a clue; critical info is in SE’s head. Manual update of Excel file MEL + manual consistency check of equipment list against all PowerPoint block diagrams. Similar to ‘dry mass’ above, but also uses model of scenario Same as ‘dry mass’ above. 26

27. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Effective Model vs. Effective Design An effective model provides sufficient representation to answer the questions being posed (e.g. is it a good design?) An effective design satisfies its requirements in a cost- effective way An effective model shows a flawed design to be flawed 27 Source: Sanford Friedenthal Example: A CAD model of a chair is a high-quality representation of the chair geometry … but it could be a poor design e.g. can’t handle the load Example: A CAD model of a chair is a high-quality representation of the chair geometry … but it could be a poor design e.g. can’t handle the load

28. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What is SysML? Is SysML required for MBSE?

29. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What is SysML? (1 of 3) SysML is a visual modeling language that is both human- and computer understandable, and extensible. “SysML is the new industry-standard language designed specifically to support modern systems engineering.” 29 SysML™ = Systems Modeling Language SysML is a general-purpose modeling language that supports the specification, design, analysis, and verification of systems that may include hardware, software, data, personnel, procedures and facilities.” (Bran Selic, Malina Software Corporation) (Friedenthal, Moore & Steiner, A Practical Guide to SysML)

30. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What is SysML? (2 of 3) Title: “Modeling of embedded systems with UML and SysML” (translated from German) SysML is a subset of UML with extensions to support requirements for systems modeling 30 UML 2 SysML 16 diagrams 9 diagrams 42 extensions Use of SysML facilitates systems-software communication within projects since UML is the de facto standard software modeling language software modeling system modeling

31. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What is SysML? (3 of 3) SysML History*: 2001: INCOSE Model Driven Systems Design workgroup decides to customize UML for systems engineering 2001: INCOSE and OMG chartered the OMG Systems Engineering Domain Special Interest Group 2004: The SysML Partners distributed their first open source SysML specification drafts 2007: Version 1.0 language specification released by OMG 2012: Version 1.3 released by OMG * http://en.wikipedia.org/wiki/Sysml SysML History*: 2001: INCOSE Model Driven Systems Design workgroup decides to customize UML for systems engineering 2001: INCOSE and OMG chartered the OMG Systems Engineering Domain Special Interest Group 2004: The SysML Partners distributed their first open source SysML specification drafts 2007: Version 1.0 language specification released by OMG 2012: Version 1.3 released by OMG * http://en.wikipedia.org/wiki/Sysml 31 SysML is an OMG standard The Object Management Group™ (OMG) is an international, open membership, not-for-profit computer industry consortium founded in 1989 that creates standards for for software used in government and corporate environments to enable interoperability. http://www.omg.org/ The Object Management Group™ (OMG) is an international, open membership, not-for-profit computer industry consortium founded in 1989 that creates standards for for software used in government and corporate environments to enable interoperability. http://www.omg.org/ Title: Model-based system development using SysML (translated from German)

32. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What can a SysML model represent? 32 Adapted from Sanford Friedenthal Structural composition Interconnection Classification Structural composition Interconnection Classification Structure Requirements Relationships to other requirements, interfaces, components, analyses, and test cases Requirements Relationships to other requirements, interfaces, components, analyses, and test cases Constraints on physical and performance properties Function-based behavior Message-based behavior State-based behavior Function-based behavior Message-based behavior State-based behavior Behavior Requirements Parametrics Note: The need to represent such aspects has always been part of systems engineering. SysML simply provides a formal language for doing so.

33. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Four Pillars of SysML (and interrelations) Structure Behavior RequirementsParametrics allocate satisfy value binding Verify 33

34. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What SysML is Not Not intended to replace current investment in modeling in other engineering disciplines. (Nor could it.) –Mechanical, electrical, thermal, telecom, navigation, attitude control, etc. Not a methodology or a tool –SysML is a language –SysML is methodology-neutral and tool-independent Not required for MBSE –SysML is designed to support MBSE, but MBSE does not require SysML 34 “A standardized and robust modeling language is considered a critical enabler for MBSE. The Systems Modeling Language (OMG SysML™) is one such general purpose modeling language …” A Practical Guide to SysML, 2012 “A standardized and robust modeling language is considered a critical enabler for MBSE. The Systems Modeling Language (OMG SysML™) is one such general purpose modeling language …” A Practical Guide to SysML, 2012 This training module uses SysML to help explain MBSE, but other system modeling languages could be used as well.

35. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Myths about MBSE (part 2) Myth 4: MBSE is just about using SysML No. SysML is a modeling language that can be used to describe systems, whereas MBSE is the application of modeling languages, methods, tools, and domain knowledge to analyze, specify, design, and verify systems. Myth 5: There’s nothing really new in MBSE; SE’s already create many kinds of models Modeling is not new. What’s new is the existence of formal modeling languages for describing systems, and the role that a system model can play in integrating information from other models. Myth 6: SysML tools are just new drawing tools, similar to the Visio™ and PowerPoint™ tools No. Information in SysML diagrams is stored in a database and can be analyzed for consistency and completeness, and processed to generate reports. Data can be exchanged with other discipline models. 35

36. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Making it Real: A case study in MBSE Examples are from the Europa study, courtesy of Todd Bayer

37. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE Case Study Mission Domain Top-level view: “front door” to more detailed views Composite association Reference association Composite association Reference association 37

38. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE Case Study Flight System Composition (a.k.a. System Block Diagram) Authoritative statement of flight system composition Mass & Power reports are produced directly from the underlying model Internal block diagram (ibd) shows connections among elements 38

39. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE Case Study Subsystem Deployment This block diagram is a view of the flight system showing only the powered elements 39

40. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE Case Study Equipment List and Mass Margin Report Produced directly from the system model Reports mass of payload, spacecraft, and propellant, and computes margin relative to launch vehicle capability Legend: –CBE: Current Best Estimate –Cont: Contingency (percentage) –MEV: Maximum expected value 40

41. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE Case Study Model-Generated Power Margin Analysis The Europa Clipper System Model Including component power characterizations and mission scenarios Discipline Specific Energy and Power Margin Functions in an accessible format (e.g. Mathematica) Mission Specific Energy and Power Margin Analysis Results Energy Power Margin Analysis Mathematica/Ma ple/Matlab Key system metrics (such as power margin) are derived early in the mission lifecycle, using reliable analysis functions, produced rapidly with little effort. 41

42. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE Case Study Modeling Power Load Characterization 42 Associates a system-level power load characterization with a power load characterization of each component

43. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE Case Study Mission Scenario Modeling Think of an orbit as a flower with petals Define each piece of a flyby petal as a system level power mode. Define the flyby scenario as a timeline in terms of the system level power modes. 43

44. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE Case Study Model-Generated Power Margin Analysis 44 Battery SOC Total Load + 40% Power Generation CBE Total Load Telecom Payload State of Charge (SOC) 7 day Petal Scenario Week 1 Week 2 Power (W) Timestep (hours)

45. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE Case Study Work Breakdown vs. Product Breakdown Subsystems seldom delivered as integrated components Better understood as aggregations of convenience, in this case aggregations of delivery responsibility Work breakdown (WBS) Example: Flight system WBS element authorizes Power Subsystem WBS element.” Work breakdown (WBS) Example: Flight system WBS element authorizes Power Subsystem WBS element.” Product supplier Example: Power Subsystem WBS element supplies products: Battery, Power Switches, etc. Product supplier Example: Power Subsystem WBS element supplies products: Battery, Power Switches, etc. 45

46. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE How does MBSE compare to traditional SE? What’s happening in industry?

47. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Modeling in Traditional Systems Engineering “Models have been used as part of document-based systems engineering approach for many years, and include functional flow diagrams, behavior diagrams, schematic block diagrams, N 2 charts, performance simulations, and reliability models, to name a few.” * “However, the use of models has generally been limited in scope to support specific types of analysis or selected aspects of system design. The individual models have not been integrated into a coherent model of the overall system.” * * A Practical Guide to SysML. Friedenthal, Moore and Steiner. 47

48. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE: Consistency and Continuity Specifications Interface requirements System design Analysis & Trade-off Test plans Past Future Revision by GIT; Original Source: OMG SysML Tutorial (June 2008). Reprinted with permission. Copyright © 2006-2008 by Object Management Group. Transition to a rigorous system model helps ensure consistent modeling across disciplines and continuous access to this system model between system levels and across the life cycle 48

49. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE: What’s new about it? Modeling is not new –Flight projects have a strong legacy of modeling (structural, thermal, circuit design, mission design…) –Systems Engineering uses models also, though typically limited in scope and duration. A set of requirements, an excel spreadsheet, and a PowerPoint drawing are all models. What is new is … –the availability of a formal modeling language which can describe systems, and –the information engineering standards and tools which enable integration of a system model with existing discipline models. Page 49

50. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What MBSE Practitioners Say (1 of 2) It Enhances Communication –A single, authoritative source of information keeps team on same page –Standard documents are kept consistent and up-to-date –More complete transmission of concepts & rationale from one phase to next It Improves Productivity –Less hunting for information. –Time-consuming project documents/reports become trivial to generate It Improves Quality –Earlier detection of inconsistencies (‘escapes’) due to clearer semantics –“One thing that I’ve found is that the process of modeling leads to ‘escape discovery’. …capturing the details leads to a greater understanding of the system and makes errors or potential problem areas ‘pop out’.” 50

51. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What MBSE Practitioners Say (2 of 2) It Supports Integration –Provides consistent definition of system to integrate with discipline models, including cost models and science margin models It Helps Manage Complexity –Different views address the concerns of different stakeholders It Enables Reuse of Institutional Knowledge –MBSE enhances reuse of intellectual property (model elements embody hard-earned technical expertise) It Attracts Early Career Talent –MBSE forms a bridge from college education to institutional practices –MBSE methods being taught to the current generation of engineering students –New hires are prominent among the early adopters 51

52. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What Boeing Says Why MBSE now?  System definitions have moved from simple to highly integrated & complex  Customers’ drive to open architectures and increased affordability  Faster delivery of adaptable, interoperable systems Measurable Benefits  Comprehensive integrated architectures resulted in a significant reduction in interface definition changes after initial design  Detailed functional architectures resulted in reductions of actual program test hours  MBSE used for early identification of system performance impacts, resulting in a more effective network performance  Potential design issues were identified early in the lifecycle 52 Source : Christi Gau Pagnanelli, Barbara Sheeley, Ronald Carson, The Boeing Company, “Model-Based Systems Engineering in an Integrated Environment”

53. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE What Lockheed Says Case Study from LM Aeronautics  Collected data from four real aerospace and defense programs at LM  Three programs used traditional approach; one software- intensive system used model-based Measurable Benefits  Quality: model-based approach had fewer defects per requirement  Software Quality: model-based approach had far fewer defects per KSLOC  Affordability: When normalized for system size, the model-based-produced system was developed at a significantly reduced cost 53 Source: Lenny Delligatti, Lockheed Martin Corp., “Model-Based Systems Engineering (MBSE) with SysML”

54. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE In a 2009 SysML survey, 45 companies participated: No longer small pilot studies! Actively used in most large companies in Aerospace, Defense, Automotive MBSE is becoming part of day-to-day engineering practice MBSE in Industry Space Systems:23% Aircraft: 20% Defense: 20% Automotive: 7% Other: 30% Project Duration 1 mo – 1 year:20% 1 year – 3 years: 35% > 3 years: 45% Project Size < 10 people:28% 10 – 100:40% 100 – 1000: 22% > 1000 people: 10% (Data Source: Robert Cloutier — http://www.omg.org/cgi-bin/doc?syseng/2009-12-04) 54

55. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Why is MBSE Being Used?  Large majority (55.2%) cited the opportunity to improve Systems Engineering efforts as the reason for using modelling. When asked what the primary purpose of the model was, the majority said it was specifically to improve the quality of requirements and design to reduce downstream defects Page 55

56. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE The Value of MBSE: From the SE Community MBSE Improves Productivity –Single system model is authoritative, unambiguous, and durable Less time spent looking for information –System model promotes communication (single source of truth) Keeps whole team on the same page –Documents and charts are generated from the model Reduces time “wasted” on making slides for gate reviews –Standard analyses can be run frequently –Gate transitions are more seamless: Formulation  Implementation  Ops MBSE Improves Quality and Reduce Risk –Industry-standard notation reduces misunderstanding –System-level validation can be done early –Model is analyzable, unlike powerpoint/visio, so it can support many kinds of checks (completeness, consistency, correctness) –Documents kept up-to-date by generating them from the model 56

57. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Long ago, systems and subsystems were on equal footing Over time, computers allowed pretty much all the domains − except systems − to build rigorous modeling capabilities. –Systems is the last to get this rigor because it’s the broadest, most conceptual, and has by definition the full complexity of the system to deal with. So it’s the hardest one to get rigorous about. SE has been at a disadvantage because of this –Lacking this quantitative rigor, SE has had to rely too heavily on intuition, overemphasizing the Art and neglecting the Science SE needs to claim the rigor of its domain to restore balance –Otherwise our systems will continue to be assemblages of components whose performance and behavior must be discovered after assembly. MBSE provides this rigor A Historical Perspective on SE and MBSE Source: Todd Bayer (JPL) 57

58. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Observed Benefits of MBSE (1 of 2) 1.Modern modeling languages have clearer semantics than common boxes-and-lines diagrams, reducing miscommunication 2.Consistent, single source of information keeps team on same page and reduces time spent getting answers 3.Earlier detection of inconsistencies because models can be analyzed with respect to calculations, policies, rules, patterns, etc. 4.Documents are kept up-to-date because they can be auto-generated from the system model 58

59. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Observed Benefits of MBSE (2 of 2) 5.System model supports multiple views to address different stakeholder concerns, and all views refer to same model elements, so changes in an element appear on all views 6.Model-based simulation of state machines enables debugging and refinement of behavioral requirements 7.System model evolves across life-cycle and may guide similar future projects 8.System model helps to better manage complexity Summary Formal systems models offer these benefits because they introduce additional consistency and continuity, and because they are both human- and computer-understandable, and logically verifiable Summary Formal systems models offer these benefits because they introduce additional consistency and continuity, and because they are both human- and computer-understandable, and logically verifiable 59

60. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Comparison Summary 1.MBSE does not replace traditional SE Rather, MBSE formalizes part of SE 2.MBSE combines traditional methods and best practices with rigorous modeling techniques 3.Formal systems models offer these benefits because they introduce additional consistency and continuity, and because they are both human- and computer- understandable, and logically verifiable 60

61. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Management Issues Implications for projects Infusion challenges Lessons learned

62. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE implications for projects How does MBSE affect… deliverables? project schedule/milestones? project organization? processes (e.g. design, reviews, CM, model mgmt, methodology…)? infrastructure? metrics? 62

63. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE implications for projects (1 of 6) How does MBSE affect deliverables? Project still has to produce deliverables for each review Some documents may be generated automatically from system model –This ensures that design and documents are kept in sync HTML Web Pages Simulation & Analysis Ex: Mathematica Audits Reports System Model 63 Model Transformers Model Transformers

64. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE implications for projects (2 of 6) How does MBSE affect project schedule? Schedule time and resources to deploy infrastructure and train workforce Model development becomes infused within the schedule since models are an integral part of the technical baseline 64

65. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE implications for projects (3 of 6) How does MBSE affect project organization? Everyone needs training, but not to the same depth Different levels of training for different levels of modeling SysML Models Understand and express concepts using SysML standard notation EVERYONE Collaborate and develop models with help from core team MOST SEs including leadership CORE TEAM Applies best practices, contributes to production models 65

66. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE implications for projects (4 of 6) Does MBSE affect reviews? It can, but doesn’t have to –Can still conduct conventional reviews Generate views from the system model that address different stakeholders’ concerns Leverage the model by reviewing the model itself –Reduces non-productive effort in preparing for a review Reviewers Models 66

67. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE implications for projects (5 of 6) How does MBSE affect infrastructure? Need: –System modeling tool(s) –Training (in modeling and in tool usage) –Standards (modeling style guide, model management) –Methodology* * See “Survey of Model-Based Systems Engineering (MBSE) Methodologies”, J. A. Estefan, 2008, INCOSE. http://www.omgsysml.org/MBSE_Methodology_Survey_RevA.pdf SysML Modeling Guide IMCE Team Version: 9/24/11 SysML Modeling Guide IMCE Team Version: 9/24/11 67

68. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE MBSE implications for projects (6 of 6) How does MBSE affect metrics? Easier to get data from models and update metrics Example metrics –Quality of design Mass margin, power margin, data margin, cost, … –Progress of design and development effort Completeness of component specs, # use case scenarios, … –Estimated effort to complete design and development Constructive Systems Engineering Cost Model (COSYSMO) gets inputs from system model (# requirements, # use cases, etc.) –Others: Number of critical TBDs Stability of requirements and design changes over time Potential defect rates 68

69. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Myths about MBSE (part 3) Myth 7: All SE’s need to become expert modelers No. You can establish a core modeling team to build the model. All SE’s should learn how to interpret the model. Myth 8: If the model doesn’t execute, it has no value No. Just describing something in a formal modeling language immediately improves communication and understanding. A model is useful if it helps communicate the design or answer questions. 69

70. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Management Issues: Implications for projects Infusion strategy Lessons learned

71. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Infusion: a multi-pronged approach Educate and train an initial cadre of modelers –Pair domain experts with early career hires Build on grass-roots efforts Work with strong advocates and advisors consisting of international and national experts Establish an institutionally-supported modeling environment –Define modeling standards, enable collaborative modeling effort, build a reusable model repository; provide support to system model developers Identify and build applications –Develop system models that have immediate benefits to project’s needs –Put training into practice –Modelers partner with project’s system engineers to get early buy in –Use the initial application to validate the reusable modeling environment Partner with industry, INCOSE, academia and OMG to learn, contribute and stay current 71 Source: Chi Lin, JPL

72. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Integrated Model-Centric Engineering: Ops Concept Engineering Products Generate e.g., Gate products for reviews MEL/PEL Requirements & tracing State Transition Execution System Model Domain discipline models (e.g., Modelica, STK, Simulink, NX ) Develop Analyze/ Tradeoffs/Validate/Reviews CM Controlled CM Controlled Integrated Tool/model environment Modeling Development Infrastructure Models with Use Cases Engineering Data distributed (project,, Line, institution Repositories Archive Retrieve Standards Modeling template Naming conv. Modeling style guide Data exchange Use Projects build models Institution provides: 72 Source: Chi Lin, JPL

73. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Cultural Change Roadmap Contact Awareness Understanding Initial Use Adoption 1 2 3 4 5 6 7 COMMITMENT TO CHANGE TIME Mechanisms to support sustaining the change Mechanisms to support wider rollout of change Mechanisms to support measured success in piloting (i.e., initial operational environment ) Mechanisms to assure understanding (training, piloting) Mechanisms to promote awareness ( e.g., seminars, Modeling Early Adopter Group) Adapted from “Out from Dependency: Thriving as an Insurgent in a Sometimes Hostile Environment”, SuZ Garcia and Chuck Myers, SEPG Conference, 2001 Institutionalization Internalization 73

74. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Multi-Year Strategy: Capabilities Degree of Maturity Key Capabilities: 1.MBSE methodology that supports systems & software integration 2.Modeling framework that enables model/tools integration 3.Standard design views and viewpoints that support: capturing technical designs in formal models performing reviews based on formal models 4.Standard set of modeling tools are established and supported 5.CM-controlled repository populated with validated reusable models created from formulation to implementation Key Capabilities: 1.Cadre of trained MBSE modelers 2. Modeling infrastructure that facilitates collaborative modeling activities 3.Initial modeling standard 4.Modeling user’s guide 5.Initial CM-controlled model repository framework w/examples Key Capabilities: 1.A fully operational modeling Infrastructure that enables integration of system models with domain discipline analytical models, simulation/visualization models to support: Design to cost Reviews Trade study… 2. A matured model-based development methodology with training support 3. A fully CM controlled operational model repositories that collaboratively managed by projects, lines and Institution Time Continuous Practice Phase 1: Building Phase II: Performing Phase III: Integrating Setting Expectations: Such an effort takes time to achieve 74 Source: Chi Lin, JPL

75. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Myths about MBSE (part 4) Myth 9: MBSE is an all-or-nothing commitment No. MBSE is not a single thing that you adopt all at once and then deal with the consequences. You have a lot of latitude in choosing when and where to apply it, and bounding the risks in transition. MBSE involves a cultural change; it can progress step by step. 75

76. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Management Issues: Implications for projects Infusion strategy Lessons learned

77. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Lessons Learned from Europa Study (1 of 2) 1.Investment is crucial –Europa study benefitted from years of local investment in tools, modeling environment, and training 2.Unity of leadership is essential –Management must be willing to pay the startup costs and give time for the effort to pay dividends 3.Best way to start modeling is to hire people who already know how to do it –Later infusions will benefit from an experienced pool of engineers 4.Team organization matters –3-tiers: small set of core modelers, larger set of modeling-savvy SEs, within larger set of project personnel 5.Everyone needs training, but not to the same depth 77 Source: Todd Bayer (JPL)

78. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Lessons Learned from Europa Study (2 of 2) 6.Best way to figure out how to apply MBSE: do it for real –“Shadow pilots” would not have been as helpful –Pressure to deliver real engineering products forces discovery and resolution of problems not likely encountered in a shadow 7.Keep the focus on project deliverables, and model only as far as you need to answer the questions –This may need to be constantly reinforced 8.Description first, then analysis –Just describing something in a formal model language immediately improves communication and understanding 9.Separate models from analyses –Mass analysis program is independent of system details 10.Real examples are powerful –Much more effective at conveying understanding and building support Source: Todd Bayer (JPL) 78

79. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Lessons Learned: Strategy Young engineers are already attuned to system modeling  the transition to MBSE is happening whether we help or not  pair young engineers (modelers) with graybeards (subject matter experts) Collaboration has been essential (industry, other space agencies, academia) Infusion can be gradual, both in time, and in project space benefits are evident even when systems modeling is used in a modest way on a single subsystem  the simple act of creating a formalism is by itself a significant help in communication and understanding  Culture change does not follow a project life-cycle 79

80. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Lessons Learned: Just Modeling Isn’t Enough …we also have to agree on… Ontology –What concepts are important to us? –What properties and relationships do those concepts have? –How do we name concepts and properties? Notation and exchange syntax Tools and model repository –How do I create models? –Where can I store my models? –Where can I find other models and relate to their content? Model data access mechanisms Model validation rules and constraints Configuration management procedures Relationships between engineering deliverables and model content …we model to get work done… 80

81. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Summary

82. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Audience Participation What are your take-aways? 82

83. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Take-Aways MBSE is systems engineering, aided by a system model –MBSE formalizes part of systems engineering A system model … –helps manage complexity and risk –improves communication within a team and with stakeholders –provides a consistent definition of the system that integrates information from discipline models –supports analyses (if organized appropriately) –helps couple technical design to programmatics Need infrastructure: –Tools, training, standards, methodology Multi-pronged, evolutionary infusion strategy recommended –Culture change takes time 83

84. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE For more information MBSE Community of Practice on NEN –https://nen.nasa.gov/web/se/mbse These slides –https://nen.nasa.gov/web/se/mbse/documents OMG MBSE Wiki –http://www.omgwiki.org/MBSE/doku.php OMG SysML Official Site –http://www.omgsysml.org/ NIMA: NASA Integrated Model-centric Architecture –OCE initiative to leverage/coordinate four communities of practice: MBSE, Modeling & Simulation, CAD and PDLM –https://nen.nasa.gov/web/se/nima 84

85. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Outline of MBSE Training Module 2 System models –Purpose, contents, types, integration Good system models –What makes a system model good? SysML basics and customization –Specializing SysML for flight projects: the IMCE ontologies Methodologies and NASA systems engineering process –Impact of MBSE and system modeling on NPR 7123 Summary System models –Purpose, contents, types, integration Good system models –What makes a system model good? SysML basics and customization –Specializing SysML for flight projects: the IMCE ontologies Methodologies and NASA systems engineering process –Impact of MBSE and system modeling on NPR 7123 Summary Title: Introduction to System Modeling 85

86. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE The End Systems Engineering with System Models: An Introduction to Model-Based Systems Engineering

87. Model-Based Systems Engineering Systems Engineering with System Models: An Introduction to MBSE Acronyms FS: Flight System IMCE: Integrated Model-Centric Engineering (JPL) INCOSE: International Council on Systems Engineering MBE: Model-Based Engineering MBSE: Model-Based Systems Engineering NDIA: National Defense Industrial Association NEN: NASA Engineering Network NICM: NASA Instrument Cost Model NIMA: NASA Integrated Model-centric Architecture OCE: Office of Chief Engineer OMG: Object Management Group SE: Systems Engineering SEWG: Systems Engineering Working Group (NASA) SysML™: Systems Modeling Language (OMG) UML: Unified Modeling Language 87